Two weeks after touching down triumphantly and safely inside Gale Crater, beside the 18,000-foot peak of Aeolis Mons (‘Mount Sharp’), NASA’s Curiosity rover finally flexed her robotic arm on Monday. It was the first occasion on which the 7-foot-long mechanical device, which boasts an X-shaped ‘turret’ for five sophisticated instruments, has been deployed in any environment since before Curiosity’s November 2011 launch. The success of the test places the rover and her science teams in an excellent position of strength for the start of their historic and much-anticipated ‘First Drive’ to the Glenelg site in the coming days.
“It worked just as we planned,” exulted Louise Jandura, sample system chief engineer at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “From telemetry and from the images received this morning, we can confirm that the arm went to the positions we commanded it to go to.” Monday’s exercise checked the arm’s motors and joints, which have the capability to spin the 2-foot-wide, 66-pound turret of instruments through a 350-degree turning range. Two of these instruments – the Canadian Alpha Particle X-ray Spectrometer (APXS) and NASA’s Mars Hand Lens Imager (MAHLI) – will irradiate samples, spectrally map re-radiated X-rays and acquire close-up, high-resolution images of rocks and soils at microscopic levels. Meanwhile, a percussion drill, a brush and mechanisms will scoop, sieve and portion samples for transfer to the rover’s internal laboratory.
Although its time on Mars is still young, and a ‘primary’ mission lasting some two Earth-years lies ahead, Curiosity and the scientists, technicians and engineers responsible for her care on the surface of an alien world are eager to get going. Just last week, Glenelg was selected as the destination for its First Drive. This area is geologically significant, since it is marked by a natural intersection of three different terrain types, including layered bedrock, which offers a tantalising opportunity for Curiosity’s first rock-drilling.
And that, said the mission’s principal investigator, John Grotzinger, of the California Institute of Technology, is the big deal. “With such a great landing spot in Gale Crater,” he told journalists last week, “we literally had every degree of the compass to choose from for our first drive. You can only go one place for the first drilling of a rock sample on Mars. That first drilling will be a huge moment in the history of Mars exploration.”
Glenelg lies a mere 1,300 feet east-southeast of Curiosity’s present position and, despite this relative proximity, it may take up to two months for the rover to get there, whereupon it will spend several weeks conducting in-situ scientific investigation. The robotic arm will be a key player in that investigation, as it delivers the first samples into the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) devices. The former is actually the largest of Curiosity’s ten instruments; a joint US-French effort, it will analyse specimens, separate individual gases into their molecular components and measure oxygen and carbon isotope ratios in the Martian atmosphere.
“We’ve had to sit tight for the first two weeks since landing,” said Matt Robinson of JPL, the lead engineer for the robotic arm testing and operations, “while other parts of the rover were checked out, so to see the arm extended in these images is a huge moment for us. The arm is how we are going to get samples into the laboratory instruments and how we place other instruments onto surface targets.”